Electrode including nanostructures for rechargeable cells
A lithium ion battery electrode includes silicon nanowires used for insertion of lithium ions and including a conductivity enhancement, the nanowires growth-rooted to the conductive substrate.
1. A lithium ion battery electrode comprising:
a conductive substrate; and
silicon-containing nanowires substrate-rooted to the conductive substrate, the silicon-containing nanowires having variable cross-sectional dimensions along the length of the silicon-containing nanowires and having tapered profiles with wider ends and narrower ends such that the silicon-containing nanowires taper from the wider ends to the narrower ends,
wherein one of the ends of each nanowire is substrate-rooted to the conductive substrate to provide conductive attachment and mechanical support to the silicon-containing nanowires with respect to the conductive substrate and the other of the ends of each nanowire is off the conductive substrate and wherein the silicon-containing nanowires further comprise a silicide.
2. The electrode of claim 1 , wherein the silicon-containing nanowires each comprise a silicide core and a silicon shell.
3. The electrode of claim 1 , wherein the conductive substrate comprises nickel.
4. The electrode of claim 1 , wherein the conductive substrate is provided in the form of a structure selected from the group consisting of a mesh, a perforated sheet, a foam, and a felt.
5. The electrode of claim 1 , the silicon-containing nanowires comprise substrate-rooted cores and a layer of an electrochemically active material coating the substrate-rooted cores.
6. The electrode of claim 5 , wherein the electrochemically active material comprises a material selected from the group of consisting silicon, tin, and germanium.
7. The electrode of claim 6 , wherein the substrate-rooted cores comprise a silicide, and wherein the electrochemically active material consists essentially of silicon.
8. The electrode of claim 1 , further comprising a shell coating the silicon-containing nanowires.
9. The electrode of claim 8 , wherein the shell comprises a carbon-containing material.
10. The electrode of claim 1 , wherein the silicon-containing nanowires have an average aspect ratio of at least about ten.
11. The electrode of claim 1 , wherein the silicon-containing nanowires have an average cross-sectional dimension of between about 1 nanometer and 10 microns on average.
12. The electrode of claim 1 , wherein the silicon-containing nanowires form a layer over the conductive substrate, the layer having porosity of less than about 75 percent.
13. The electrode of claim 1 , wherein the silicon-containing nanowires have an average length of at least about 100 micrometers.
14. A lithium ion battery electrode comprising:
a conductive substrate; and
silicon-containing nanowires substrate-rooted to the conductive substrate, the silicon-containing nanowires having variable cross-sectional dimensions along the length of the silicon-containing nanowires and having tapered profiles with wider ends and narrower ends such that the silicon-containing nanowires taper from the wider ends to the narrower ends,
wherein one of the ends of each nanowire is substrate-rooted to the conductive substrate to provide conductive attachment and mechanical support to the silicon-containing nanowires with respect to the conductive substrate and the other of the ends of each nanowire is off the conductive substrate and wherein the silicon-containing nanowires consist essentially of silicon.
15. The electrode of claim 14 , wherein the average cross-sectional dimension of the wider ends is below the silicon fracture limit.
16. The electrode of claim 1 , wherein the silicon-containing nanowires are growth-rooted to the conductive substrate.
17. The electrode of claim 1 , wherein the wider ends of the silicon-containing nanowires are substrate-rooted to the conductive substrate.
18. The electrode of claim 1 , wherein the narrower ends of the silicon-containing nanowires are substrate-rooted to the conductive substrate.
19. The electrode of claim 1 , wherein the conductive substrate and the silicon-containing nanowires have different compositions.
20. A lithium ion battery electrode comprising:
a conductive substrate; and
silicon-containing nanowires substrate-rooted to the conductive substrate, the silicon-containing nanowires having variable cross-sectional dimensions along the length of the silicon-containing nanowires and having tapered profiles with wider ends and narrower ends such that the silicon-containing nanowires taper from the wider ends to the narrower ends,
wherein one of the ends of each nanowire is substrate-rooted to the conductive substrate to provide conductive attachment and mechanical support to the silicon-containing nanowires with respect to the conductive substrate and the other of the ends of each nanowire is off the conductive substrate and wherein the conductive substrate has a conductivity of at least 10 3 S/m.
21. The electrode of claim 20 , wherein the silicon-containing nanowires further comprise a carbide.
22. The electrode of claim 20 , wherein the silicon-containing nanowires each comprise a silicide core and a silicon shell.
23. The electrode of claim 20 , the silicon-containing nanowires comprise substrate-rooted cores and a layer of an electrochemically active material coating the substrate-rooted cores.
24. The electrode of claim 23 , wherein the electrochemically active material comprises a material selected from the group of consisting silicon, tin, and germanium.
25. The electrode of claim 24 , wherein the substrate-rooted cores comprise a silicide, and wherein the electrochemically active material consists essentially of silicon.
26. The electrode of claim 23 , wherein the substrate-rooted cores comprise a silicide.
27. The electrode of claim 20 , wherein the wider ends of the nanowires are substrate-rooted to the conductive substrate.
28. The electrode of claim 20 , wherein the narrower ends of the nanowires are substrate-rooted to the conductive substrate.
29. A lithium ion battery comprising:
a first electrode comprising the electrode of claim 20 ;
a second electrode; and
an electrolyte.
30. The electrode of claim 14 , wherein the silicon-containing nanowires have an average aspect ratio of at least about ten.
31. The electrode of claim 12 , wherein the silicon-containing nanowires have an average length of at least about 100 micrometers.
32. A lithium ion battery comprising:
a first electrode comprising the electrode of claim 1 ;
a second electrode; and
an electrolyte.